The Design of Requirements Modelling Languages: How to Make Formalisms for Problem Solving in Requirements Engineering

285 Pages·2015·12.799 MB·

by  Ivan Jureta (auth.)

Ivan Jureta
The Design of
Requirements
Modelling
Languages
How to Make Formalisms for Problem Solving
in Requirements Engineering
The Design of Requirements Modelling Languages
Ivan Jureta
The Design of Requirements
Modelling Languages
How to Make Formalisms for Problem
Solving in Requirements Engineering
123
IvanJureta
DépartementdesSciencesdeGestion(B423)
UniversitédeNamur
Namur
Belgium
ISBN978-3-319-18820-1 ISBN978-3-319-18821-8 (eBook)
DOI 10.1007/978-3-319-18821-8
LibraryofCongressControlNumber:2015940984
SpringerChamHeidelbergNewYorkDordrechtLondon
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Preface
You have a requirements engineering problem to solve, if (i) you have unclear,
abstract, incomplete, potentially conflicting information about expectations of var-
iousstakeholders,andabouttheenvironmentinwhichtheseexpectationsshouldbe
met,(ii)youknowthatthereispresentlynosolutionwhichmeetstheseexpectations
and (iii) you need to define and document a set of clear, concrete, sufficiently
complete, coherent statements, often called requirements; so that a system is made
andoperatedtosatisfythesestatementswillinfactmeetstakeholders’expectations.
Requirementsengineeringproblemsareill-structuredproblems.Solvingthemis
hard. You typically have to do many complex and interdependent tasks, such as
elicitation, categorization, evaluation, prioritization, negotiation and prediction.
Solving a requirements engineering problem relies on intuition and creativity,
butmoreimportantlyforthisbook,itmobilizesexperientialknowledgewhichwas
shaped by your problem-solving experience. This book shows how to create arti-
ficial intelligence (AI) fromthat experientialproblem-solvingknowledge.You can
seesuchAIasanassistanttowhichyoucandelegatesomeproblem-solvingtasks.
AI is a combination offormal languages or formalisms used to represent (make
models of) problem-solving information and algorithms used to carry out trans-
formations of, and computations on those representations. Formalisms and algo-
rithms preserve and automate the application of that experiential problem-solving
knowledge you built into them.
ThisbookfocusesontheformalismspartofAI.Onthealgorithmside,itshows
how models made with the various formalisms can be translated, and translations
fed into already well-known and general purpose algorithms.
ThisbookwasinfluencedbyresearchwhichIcarriedoutwithJohnMylopoulos
and Alexander Borgida. I co-authored papers on problem solving in requirements
engineeringwiththem,aswellaswithNeilErnst,StéphaneFaulkner,AnnaPerini,
Pierre-Yves Schobbens, Alberto Siena, Angelo Susi, and many others. They have
all shaped the content of this book in various ways. This does not mean that we
agree on the ideas which I present here.
March 2015 Ivan Jureta
vii
Contents
1 Requirements Problem Solving . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Motivation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Problem Situations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.3 Problem-Solving Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.4 Solution Situations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.5 Requirements Problem Solving. . . . . . . . . . . . . . . . . . . . . . . 6
2 Problem-Solving Automation with Artificial Intelligence. . . . . . . . 9
2.1 Automation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.2 Ill-Structured Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.3 Well-Structured Problems . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.4 Well-Structured Subproblems. . . . . . . . . . . . . . . . . . . . . . . . 15
2.5 Case-Specific and Recurrent Tasks . . . . . . . . . . . . . . . . . . . . 17
2.6 Languages and Algorithms. . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.7 Artificial Intelligence. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3 Problem and Solution Concepts in Requirements Engineering . . . 21
3.1 Requirements Engineering . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.2 Problem and Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.2.1 Problem. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.2.2 Solution. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
3.3 System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
3.4 Model. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
3.5 Default Problem and Solution. . . . . . . . . . . . . . . . . . . . . . . . 25
4 Introduction to Requirements Modeling Languages . . . . . . . . . . . 29
4.1 Formal Language . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
4.1.1 Syntax. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
4.1.2 Semantics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
4.2 Role in Problem Solving . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
4.3 Rough Historical Overview . . . . . . . . . . . . . . . . . . . . . . . . . 33
ix
x Contents
4.4 i-Star. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
4.4.1 Motivation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
4.4.2 Syntax. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
4.4.3 Semantic Domain and Mapping . . . . . . . . . . . . . . . . 40
4.4.4 Comments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
4.5 Techne . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
4.5.1 Motivation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
4.5.2 Semantic Domain and Mapping . . . . . . . . . . . . . . . . 45
4.5.3 Syntax and More Semantic Mapping. . . . . . . . . . . . . 47
4.5.4 Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
4.5.5 Formalization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
4.5.6 Comments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
5 Requirements Problem-Solving Cases . . . . . . . . . . . . . . . . . . . . . 61
5.1 Brussels Law . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
5.1.1 Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
5.1.2 Interviews Summary . . . . . . . . . . . . . . . . . . . . . . . . 63
5.1.3 Problems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
5.2 Copenhagen Sports. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
5.2.1 Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
5.2.2 Interview Summary. . . . . . . . . . . . . . . . . . . . . . . . . 67
5.2.3 Problem. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
5.3 Dubai Telecom. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
5.3.1 Interviews Summary . . . . . . . . . . . . . . . . . . . . . . . . 68
5.3.2 Problem. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
5.4 London Ambulance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
6 Checklists, Templates, and Services for Requirements
Modeling Language Design. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
6.1 Problem-Solving Services . . . . . . . . . . . . . . . . . . . . . . . . . . 73
6.2 Checklists and Templates. . . . . . . . . . . . . . . . . . . . . . . . . . . 75
6.3 Language and Module Names . . . . . . . . . . . . . . . . . . . . . . . 76
7 Relations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
7.1 Motivation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
7.2 Single Relation Language . . . . . . . . . . . . . . . . . . . . . . . . . . 78
7.2.1 Choose a Language Service. . . . . . . . . . . . . . . . . . . 79
7.2.2 Models over Fragments. . . . . . . . . . . . . . . . . . . . . . 80
7.2.3 Trivial Modeling Language . . . . . . . . . . . . . . . . . . . 82
7.3 Modular Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
7.4 Some Influence Relations. . . . . . . . . . . . . . . . . . . . . . . . . . . 89
7.4.1 Presence of Influence . . . . . . . . . . . . . . . . . . . . . . . 90
7.4.2 Direction of Influence. . . . . . . . . . . . . . . . . . . . . . . 92
7.4.3 Relative Strength of Influence . . . . . . . . . . . . . . . . . 94
7.4.4 Summary on Influence Relations . . . . . . . . . . . . . . . 98
Contents xi
7.5 Arguments in Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
7.5.1 Support and Defeat. . . . . . . . . . . . . . . . . . . . . . . . . 100
7.5.2 Accepted or Rejected . . . . . . . . . . . . . . . . . . . . . . . 105
7.6 Combinations of Relations. . . . . . . . . . . . . . . . . . . . . . . . . . 112
7.6.1 Independent Relations. . . . . . . . . . . . . . . . . . . . . . . 112
7.6.2 Interacting Relations . . . . . . . . . . . . . . . . . . . . . . . . 113
7.7 Summary on Relations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
8 Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
8.1 Motivation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
8.2 Guidelines from Arguments . . . . . . . . . . . . . . . . . . . . . . . . . 120
8.3 Composite Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
8.4 Stronger and Weaker Guidelines. . . . . . . . . . . . . . . . . . . . . . 128
8.5 Summary on Guidelines. . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
9 Categories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
9.1 Motivation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
9.2 Independent Categories . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
9.3 Taxonomy of Categories . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
9.4 In Meta-models and Ontologies . . . . . . . . . . . . . . . . . . . . . . 139
9.5 Derived Categories and Relations . . . . . . . . . . . . . . . . . . . . . 140
9.6 Enforce Category Use. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
9.7 Summary on Categories. . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
10 Valuation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
10.1 Motivation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
10.2 Propagating Binary Values. . . . . . . . . . . . . . . . . . . . . . . . . . 148
10.2.1 Binary Value Type . . . . . . . . . . . . . . . . . . . . . . . . . 148
10.2.2 Value Propagation. . . . . . . . . . . . . . . . . . . . . . . . . . 149
10.3 Combining Several Binary Value Types . . . . . . . . . . . . . . . . 156
10.3.1 Independent Value Assignments. . . . . . . . . . . . . . . . 158
10.3.2 Dependent Value Assignments. . . . . . . . . . . . . . . . . 162
10.4 Sets of Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
10.5 Constraints on Assignments. . . . . . . . . . . . . . . . . . . . . . . . . 165
10.6 Real Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167
10.7 Summary on Valuation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
11 Uncertainty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
11.1 Motivation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
11.2 Independent Random Variables. . . . . . . . . . . . . . . . . . . . . . . 173
11.3 Dependent Random Variables. . . . . . . . . . . . . . . . . . . . . . . . 180
11.3.1 Ignoring Existing Relations . . . . . . . . . . . . . . . . . . . 181
11.3.2 Using Existing Relations . . . . . . . . . . . . . . . . . . . . . 182
xii Contents
12 Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
12.1 Motivation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
12.2 Alternatives over Binary Value Types. . . . . . . . . . . . . . . . . . 189
12.3 Picks and Their Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
12.4 Several Arbitrary Value Types . . . . . . . . . . . . . . . . . . . . . . . 216
12.5 Summary on Alternatives. . . . . . . . . . . . . . . . . . . . . . . . . . . 220
13 Constraints. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223
13.1 Representing Constraints . . . . . . . . . . . . . . . . . . . . . . . . . . . 223
13.2 Constraints in Outcome Search. . . . . . . . . . . . . . . . . . . . . . . 229
13.3 Summary on Constraints . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
14 Preferences. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239
14.1 Motivation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239
14.2 Preferences and Criteria Basics. . . . . . . . . . . . . . . . . . . . . . . 240
14.2.1 Core Preference Relations . . . . . . . . . . . . . . . . . . . . 240
14.2.2 Domains of Preference Relations . . . . . . . . . . . . . . . 241
14.2.3 Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242
14.3 Representing Preferences. . . . . . . . . . . . . . . . . . . . . . . . . . . 242
14.4 Finding Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249
14.5 Better and Best Outcomes . . . . . . . . . . . . . . . . . . . . . . . . . . 254
14.6 Summary on Preferences . . . . . . . . . . . . . . . . . . . . . . . . . . . 262
15 Links to Formal Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267
15.1 Motivation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267
15.2 Models to Theories, Approach One. . . . . . . . . . . . . . . . . . . . 269
15.3 Models to Theories, Approach Two . . . . . . . . . . . . . . . . . . . 273
15.4 Risks of Mapping to Formal Theories. . . . . . . . . . . . . . . . . . 273
15.5 Summary on Formal Theories. . . . . . . . . . . . . . . . . . . . . . . . 274
References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283